From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1945964Ab3BHHO4 (ORCPT ); Fri, 8 Feb 2013 02:14:56 -0500 Received: from mail.parknet.co.jp ([210.171.160.6]:33925 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755950Ab3BHHOz (ORCPT ); Fri, 8 Feb 2013 02:14:55 -0500 From: OGAWA Hirofumi To: Namjae Jeon Cc: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Namjae Jeon , Ravishankar N Subject: Re: [PATCH v2] fat: eliminate iterations in fat_search_long and __fat_readdir in case of EOD References: <1359989028-7457-1-git-send-email-linkinjeon@gmail.com> <87bobw4ab9.fsf@devron.myhome.or.jp> Date: Fri, 08 Feb 2013 16:14:41 +0900 In-Reply-To: (Namjae Jeon's message of "Fri, 8 Feb 2013 15:34:19 +0900") Message-ID: <874nhn46qm.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Namjae Jeon writes: >> And did this work correctly about f_pos for readdir? > Yes, sure. f_pos is work correctly about each directory entry. because > after name[0] == 0x00, there are no allocated directory entires. >> >> I'm not thinking about f_pos deeply though, it may have something >> wrong. Because it stops at middle of cluster. > Plz See the below descirption about name[0] in FAT spec. > --------------------------------------------------------------------------------------------------------------------- > If DIR_Name[0] == 0x00, then the directory entry is free (same as for > 0xE5), and there are no allocated directory entries after this one > (all of the DIR_Name[0] bytes in all of the entries after this one are > also set to 0). > The special 0 value, rather than the 0xE5 value, indicates to FAT file > system driver code that the rest of the entries in this directory do > not need to be examined because they are all free. > ----------------------------------------------------------------------------------------------------------------------- > > I think that lookuping entry till the end of cluster is not needed. > Let me know your opinion. I know it though. There is seek() and broken drivers adds entries after name[0] == 0. I think we don't need to care much about broken drivers though. Even if so, kernel should not be crash, and corrupts fs more. > And Would you tell me your opinion about fat exportfs ? Ah, I was thinking I did. But it seems I didn't actually. Can you post full of series? So, I can review and probably we can start to test it. Thanks. -- OGAWA Hirofumi